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Conversion of cheese production residues into valuable biogas

Posted: 2016-11-21 17:23:55

Conversion of cheese production residues into valuable biogas

Dairy and other fatty by-products can incur hefty off-site disposal costs.   At one of the UK’s largest cheese producers, First Milk, a recently-completed on-site anaerobic digestion (AD) plant is successfully converting cheese whey and production residues into biogas for use as a local energy source.  Richard Gueterbock of Clearfleau examines the broader impact this can have on Europe’s food and drink sector. 

At First Milk’s Lake District creamery, one of the UK’s largest cheese producers (operated by farmer-owned dairy company, First Milk) a recently-completed on-site anaerobic digestion (AD) plant is converting cheese whey and production residues into biogas for use as a local energy source.

It is the latest AD plant to be installed by British bio-energy technology company Clearfleau, and has attracted much attention due to its innovative treatment of cheese residues.  By using the bio-methane generated, it supplies energy to the creamery itself and local houses.  It is a great example of decentralized energy generation adding value in the circular economy.   

 

Issues faced by First Milk

 

First Milk faced a number of issues from a financial, operational and environmental viewpoint.  Its old effluent treatment works needed capital investment to upgrade the plant and ensure compliance with Environment Agency requirements. Other pressures came from rising energy costs and a continuing decline in milk prices.  First Milk needed to reduce its overheads and bring the old treatment works up to date to take advantage of the latest, more efficient and more cost-effective technology used in processing both liquid and solid fatty residues.  There was also scope to reduce the site’s carbon footprint, cut CO2 emissions and to reduce the plant’s reliance on fossil fuels.  First Milk also needed to minimise the risk of watercourse pollution, with the plant located in an area susceptible to flooding.

 

The solution provided by Clearfleau

 

As the leading British provider of industrial AD, Clearfleau was asked to design and install an on-site anaerobic digestion (AD) facility to handle all the site’s residues.  Exclusively deployed on industrial sites, Clearfleau’s system can generate renewable energy from a range of food processing residues. 

 

The Aspatria project was funded by a separate business, Lake District Biogas, set up to develop the AD plant - the largest on-site digestion plant in the dairy sector in Europe.  Also, it is the only dedicated creamery digestion facility producing bio-methane generated entirely from its processing residues, without inclusion of additional non-dairy feedstocks.  The plant will reduce creamery fossil fuel consumption by over 25%, producing 1,000m3/ hour of biogas.

 

The Lake District Biogas plant converts bio-degradable cheese production residues into energy.  It also discharges cleansed water from the digester to the nearby river Ellen.   The limited volume of residual bio-solids generated from the plant is supplied to local farms as a source of nutrients for production of grass to feed some of the cows that supply the creamery.  This is a great example of a sustainable food production adding value to dairy residues, when prices and margins are under pressure across the EU. 

 

At the bio-energy plant 1,500 m3 of wash waters, whey and process residues per day generate over 5MW of thermal energy. Most of the biogas is upgraded to bio-methane (removing other gases to provide a thermal value comparable to natural gas) for injection into the gas grid.  It supplies the creamery’s boilers, as well as local households and businesses.  The Lake District Biogas Plant (www.lakedistrictbiogas.co.uk) enabled First Milk to address the issues with its ageing effluent treatment plant but also to save the £3m replacement cost.  It is converting fatty residues into renewable energy to power the creamery, discharging clean water to watercourse (after aerobic polishing of the digestate) and cutting emissions, while reducing watercourse pollution risk. 

 

The Lake District Biogas bio-energy plant cost over £9m, with a payback in under 5 years.  It will cut fossil fuel consumption on the site, generating 1,000m3/day of biogas, over 80% of which will be injected to the national gas grid.  Some biogas is also fed to a combined heat and power (CHP) engine to supply power to the site. 

 

Clearfleau worked with the Environment Agency to ensure compliance.  The plant has helped to secure the future of the creamery and has brought a high profile green energy project into Cumbria. 

After the recent Paris Climate Change Summit, CEO’s of global food companies stated: “We want the facilities where we make our products to be powered by renewable energy with nothing going to waste.” This project shows this is possible now and with the funding mechanism used to fund Lake District Biogas, can be used by smaller companies that frequently lack the funds available for sustainability projects in companies like Nestle or Diageo.

 

The Aspatria plant is an effective demonstration of the circular economy, reducing carbon emissions and generating renewable energy.  This proven on-site digestion process can manage process residues and this approach could extend across Europe’s food and drink sector.